Method to Use A Synergistic Composition

ABSTRACT

This invention relates to a synergistic composition made of a herbicidally effective amount of a propanil-based product, such as SUPER WHAM® and the at least one ACCase inhibitor herbicide such as CLINCHER® in an amount sufficient to facilitate the herbicidal activity of the propanil-based herbicide. It has been found that this synergistic composition, when applied to a field of rice, allows a reduction in the amount of herbicide needed, greater flexibility in timing of the application and broad spectrum of weed control.

RELATED APPLICATION

This application is a divisional application of a U.S. Ser. No.12/759,977 filed Apr. 14, 2010, is a divisional application of a U.S.Ser. No. 12/393,203 filed Feb. 26, 2009 (now abandoned), which is adivisional of U.S. Pat. No. 7,560,416 filed Sep. 21, 2005 and herebyclaims the benefit thereof and specifically incorporates this patentapplication by reference.

FIELD OF THE INVENTION

This invention relates to synergistic herbicidal combinations,particularly, such combinations for use in controlling weeds in ricecrops.

BACKGROUND OF THE INVENTION

Successful weed management is essential for economical rice production.In rice production, propanil-based products are applied at various leafstages of the weeds to prevent the growth of weeds. Propanil is aphotosystem II inhibitor that controls broadleaf, grass, and sedgeweeds. Propanil based products, such as SUPER WHAM (RiceCo, Inc.,Memphis, Tenn.) have broad spectrum grass, broadleaf weed and sedgecontact herbicidal activity, while at the same time being safe to rice.As a general rule of thumb, for every propanil susceptible grass leafpresent, up to six leaves, one pound of propanil active ingredient peracre is needed to control the weed. Propanil resistant grasses aretypically controlled by the addition of another grass herbicide toovercome resistance.

Another type of herbicides are the ACCase inhibitors such as: Cyhalofopsethoxydim, clethodim diclofop, fluazifop, fenoxaprop, quizalofop,clefoxydin and haloxyfop. ACCase inhibitor herbicides are known to beantagonistic when mixed with propanil (Kendig “New Rice Chemicals areTools, Not Programs”, MO Delta Center, Rice Oct. 16, 2002). Poor weedcontrol results have been observed with tank mixtures of ACCaseinhibitor herbicides and propanil. G. Studebaker, University of ArkansasPest Management News; (May 30, 2002); K. Smith. “Plan Ahead. Do a goodjob upfront and know your herbicide capacity,” Rice Journal (2004); CBGuy, “Profile: CLINCHER, Regiment herbicides (2003). (In Delta FarmPress.) In fact, for many ACCase inhibitor herbicides, use with apropanil based herbicide are restricted in the rate and recommendationcharts distributed by the manufactures.

SUMMARY OF THE INVENTION

When ACCase inhibitor herbicides are used at substantially lower thanlabeled rates in combination with propanil, the activity of thecombination is superior to the components when used alone. Furthermore,there are no antagonistic effects in fact they are synergistic. Thissurprising effect will broaden the options for economic weed control forrice farmers due to allowing for a wider application window (greaterflexibility in timing of application) and broader spectrum of weedcontrol, such as control of Sprangletop, a grass not normally controlledby propanil. This invention relates more specifically to a synergisticcomposition and its use to control weeds in a field of rice. Thesynergistic composition is made of as its active ingredient a herbicidalcompound. The herbicidal compound includes an herbicidally effectiveamount of a propanil based herbicide and at least one ACCase inhibitorherbicide in an amount sufficient to facilitate the herbicidal activityof the propanil based herbicide. The synergistic composition can alsoinclude as an active ingredient an effective amount of an insecticide,fungicide, bactericide, acaracide, nematicide, plant growth regulator,fertilizer, or plant nutrients.

DETAILED DESCRIPTION OF THE INVENTION

This invention relates to a synergistic composition and the use of thiscomposition to prevent the growth of weeds in a field of rice. Morespecifically, this invention involves a synergistic composition made ofa combination of a herbicidally effective amount of a propanil basedherbicide and at least one ACCase inhibitor herbicide in an amountsufficient to facilitate herbicidal activity of the propanil basedherbicide. A herbicidally effective amount is an amount of herbicidenecessary to arrest weed growth, when the herbicide is applied to theweeds. The amount of the ACCase inhibitor in this combination is anamount sufficient to facilitate herbicidal activity of the propanilbased product. It has been found that this amount is substantially belowthe label rates for the use of ACCase inhibitor. In general, substantialbelow label rates are less than half the label rates. Presently, onlyCyhalofop and Fenoxaprop are registered for use on rice in the USA andhave rate and grass recommendations for rice. The other ACCaseinhibitors are not labeled for use on a rice crop in the USA. The otherACCase inhibitors are not labeled for use on a rice crop; however, ifonly an amount sufficient to facilitate the activity of the propanilbased herbicide are used, then heretofore unavailable ACCase inhibitorherbicides can function to control weeds in a rice crop in combinationwith a propanil based herbicide.

For example, WHIP 360 (Bayer Crop Science) shows a rate and grassrecommendation chart for rice as follows:

TABLE 1 Rate and Grass Recommendation Chart for Rice Amount of WHIP ®360 Per Acre (pints) Relative to Stage of Annual Grass Weeds 1 to 3 leafto >2 tiller Grass Species 3 leaf 2 tiller or >10″ Sprangletop 0.7 pt/A0.8 pt/A 0.7 pt/A (Leptochioa spp.) to Barnyardgrass, watergrass 1.0pt/A (Echinochioa crusgalli) Broadleaf signalgrass (Brachiariaplatyphylla) Goosegrass (Eleusine indica) Jungle rice (Echinochioacolonum) Crabgrass (Digitaria spp.) Johnsongrass (10″-15″) (Sorghumhalepense) Giant foxtail (Setaria faberii) Fall panicum (Panicumdichotomiflorum) Red Rice 0.7-1.0 pt/A NOT RECOM- Oryza sativa MENDED

According to this invention, weeds are controlled in the presence of arice crop by treating the crop, the weeds, or the locus of either orboth, with a herbicidally effective amount of a synergistic combinationof a propanil-based herbicide and at least one ACCase inhibitorherbicide in an amount sufficient to facilitate the herbicidal activityof the propanil based herbicide. In general, we have found that thesynergy is demonstrated when the combination includes these twoherbicides in a weight ratio respectively of from about 1 lb. propanilto about 0.0018 to 0.04 lbs. More specifically, in the preferredembodiment, wherein the at least ACCase inhibitor is cyhalofop theweight ratio of the herbicidal compound ranges, from about 1 lb. of saidpropanil based herbicide to about 0.009 to 0.04 lbs. of cyhalofop.Additionally, in an alternative preferred embodiment, wherein the atleast ACCase inhibitor is fenoxaprop, the weight ratio of the herbicidalcompound ranges, from about 1 lb. of the propanil based herbicide to0.0018 to 0.007 lbs. of the fenoxaprop. However, it should be recognizedthat this weight ratio varies for each ACCase inhibitor, weed types,climate, soil and water conditions.

Additionally, another aspect of this invention is that lower amounts ofa propanil based herbicide is required (for the same application) if theat least one ACCase inhibitor herbicide in an amount sufficient tofacilitate the herbicide activity of the propanil based herbicide isadded to the combination. It has been found that a combination of apropanil based herbicide, with the at least one ACCase inhibitorherbicide in an amount sufficient to facilitate herbicidal activity ofthe propanil based herbicide, results in on average 20% lower propanil,than if the same propanil based product is not used in combination theat least one ACCase inhibitor herbicide in an amount sufficient tofacilitate herbicidal activity of the propanil based herbicide.

TABLE 2 Barnyard Grass 2 to 3 Leaf 3 to 4 Leaf 4 to 5 Leaf 5 to TillerQuantity 3 qt. (3 lb)     4 qt. (4 lb)     5 qt. (5 lb)     6 qt. (6lb)     Propanil Based Product (active) Quantity 2 qt. (2 lb) +  3 qt.(3 lb) +  4 qt. (4 lb) +  5 qt. (5 lb) +  Propanil Based 3 oz. (0.056lb) 4 oz. (0.074 lb) 4 oz. (0.074 lb) 5 oz. (0.093 lb) Product +CLINCHER (active)

This combination produced synergistic or unexpected control of weeds inrice when applied at various times, and to rice planted in differentways. To control the weeds, the combination may be applied prior toplanting, after planting but prior to flooding (pre-flood,post-emergence) or after emergence of the rice and flooding (post-flood,post-emergence) and may be applied to either direct seeded (drilled orsurface seeded) or transplanted rice.

To be used in combination, it is not necessary that the two herbicidesbe applied in a physically combined form, or even at the same time. Thecombination effect results so long as the two herbicides are present onthe foliage of the weeds at the same time in the rice crop, regardlessof when they were applied. Thus, for instance a physical combination ofthe two herbicides could be applied, or one could be applied earlierthan the other; however, the herbicides should be applied within 24hours for better results.

Either herbicide could thus be applied in liquid or solid form, or acombination product containing both herbicides could be produced, again,in either liquid or solid form. Typical liquid formulations includeemulsions, suspensions (including suspensions containing microcapsules),solutions, emulsifiable concentrates, and flowables. Solid productsinclude forms such as granules, wettable powders, water-dispersiblesolid products (including water-dispersible granules containingmicroencapsulated pesticides) or dusts. Both types of compositions willgenerally contain, in addition to the active herbicides otheringredients such as solvents, wetting agents, suspending agents,anti-caking agents, dispersing agents, emulsifiers, antifreeze agents,antifoam agents, and other additives.

Either herbicide, or both, may be utilized in one of a number of knownforms of controlled release compositions. Such compositions providerelatively slow or controlled release of the active ingredient into theenvironment and include, for example, encapsulations,microencapsulations, and various forms of controlled release liquid orgranules.

Compositions according to this invention may contain the two herbicidesin numerous different physical forms. In some cases, a composition maybe produced by simply physically mixing (“tank mixing”) commerciallyavailable products containing the active herbicides, for example, twoemulsifiable concentrates containing the herbicides. Alternatively, apackage may be manufactured and sold which contains overall the twoherbicides in separate containers, but packaged together, commonlytermed a “twin-pack”.

Alternatively, previously prepared compositions (“premixes”) containingthe two herbicides can be produced. Typical liquid compositions wouldinclude an emusifiable concentrate containing both herbicides, and atwo-phase emulsion (or microemulsion) with one herbicide in each phase.

However, a similar solid product containing both herbicides couldlikewise be produced, for instance, as impregnated granules. Similarly,other solid formulations such as wettable powders or dusts could beprepared.

Again similarly, using appropriate ingredients and conditions, it wouldbe possible to prepare microencapsulated products in which one or bothherbicides are contained within a microcapsule and saidmicroencapsulated products could be sold in either liquid form (i.e.,capsule suspensions) or solid form (i.e., water-dispersible granulesproduced by drying of microcapsule suspensions). One type of liquid formwould be a microcapsule suspension in which one of the herbicides iscontained within the capsules while the other is present in anonencapsulated form, in the continuous liquid phase. The types offormulations or compositions which may contain these two herbicides isnot limited by those enumerated herein, as other types of formulationswould likely be envisaged by those skilled in the art.

Additionally, other biocidically active ingredients or compositions maybe combined with the herbicidal compositions of the present inventionand used in the methods of the present invention. In addition, thesynergistic active ingredients of the present invention can also includeinsecticides, fungicides, bactericides, acaracides, nematicides, plantgrowth regulators, fertilizers and plant nutrients, or other herbicides,especially herbicides known to be useful for controlling weeds in a ricecrop. Common partner products added to propanil products to controlgrasses larger than six leaves and to control propanil resistant grassesinclude but are not limited to thiocarbamates (such as molinate andthiobencarb), chloroacetamides (such as butachlor) and auxins (such asquinclorac).

The control of weeds by the combination of the propanil based productand an amount of at least one ACCase inhibitor herbicide, is illustratedby the following examples:

Example 1

In a small plot test in Arkansas a composition containing cyhalofop(formulated as CLINCHER SF containing 2.38 pounds of activeingredient/gallon) when applied to a weedy rice plot at the highrecommended rate of 15 fluid ounces/acre (0.279 pounds ai/acre) tocontrol 2-3 leaf barnyard grass controlled the grasses but provided no(0%) control of the broadleaf weeds and sedges present at the time ofapplication. While a composition containing propanil (formulated asSUPER WHAM containing 4 pounds of active ingredient/gallon) pluscyhalofop (formulated as CLINCHER SF containing 2.38 pounds of activeingredient/gallon) was applied as a tank mix to a weedy rice plot tocontrol 2-3 leaf barnyard grass at 3 pounds propanil plus 0.070 poundscyhalofop resulted in 100% control of all grasses, broadleaf weeds andsedges present at the time of application. Note that the labelrecommended rate for CLINCHER SF for controlling grasses in the 2-3 leafstage is 13.5 fluid ounces/acre (0.251 pounds cyhalofop/acre). The useof 0.07 pounds cyhalofop/acre in combination with 3 pounds of propanilis approximately 3.6 times less cyhalofop than the label recommendedrate.

Example 2

In a small plot test in Arkansas a composition containing fenoxaprop(formulated as RICESTAR containing 0.58 pounds of activeingredient/gallon) when applied to a weedy rice plot at the highrecommended rate of 17 fluid ounces/acre (0.077 pounds ai/acre) tocontrol 3-4 leaf barnyard grass controlled the grass species butprovided no (0%) control of the broadleaf weeds and sedges present atthe time of application. While a composition containing propanil(formulated as SUPER WHAM containing 4 pounds of activeingredient/gallon) plus fenoxaprop (formulated as RICESTAR containing0.58 pounds of active ingredient/gallon) was applied as a tank mix to aweedy rice plot to control 8-14 leaf barnyard grass at 6 pounds propanilplus 0.010 pounds fenoxaprop resulted in 100% control of all grasses,broadleaf weeds and sedges present at the time of application. Note that6 pounds of propanil/acre alone would not be expected to controlbarnyard grass above 6 leaves and the highest label recommended rate forfenoxaprop controlling grasses at the 3 to 4 leaf stage is 17 fluidounces product/acre (0.077 pounds active ingredient/acre). However,combining the high rate of propanil (6 pounds/acre) with fenoxaprop at0.01 pounds/acre, or approximately 7.7 times below the highest recommendrate, provided complete control of the weeds present.

Example 3

In a small plot test in Arkansas a composition containing propanil(formulated as Propanil 36 EC containing 3 pounds of activeingredient/gallon) plus fenoxaprop (formulated as WHIP 360 containing0.57 pounds of active ingredient/gallon) was applied as a tank mix to aweedy rice plot to control 4 leaf barnyard grass at 3 pounds propanilplus 0.009 pounds fenoxaprop. The results are shown in Table 2. Notethat the label recommended rate for WHIP 360 for controlling grasses inthe 4 leaf stage is 12.8 fluid ounces/acre (0.057 poundsfenoxaprop/acre). The use of 0.009 pounds fenoxaprop/acre in combinationwith 3 pounds of propanil is approximately 6.3 times less fenoxapropthan the label recommended rate.

TABLE 3 % CONTROL % CONTROL WEED GROUP WEED 5 DAA* 22 DAA* GrassBarnyard grass 98 90 Grass Broadleaf 94 91 signalgrass Sedge Sedge 100na Broadleaf Weed Hemp Sesbania na 100 DAA* = Days after Application

Example 4

In a commercial field application by air in Arkansas a compositioncontaining propanil (formulated as SUPER WHAM containing 4 pounds ofactive ingredient/gallon) plus cyhalofop (formulated as CLINCHER SFcontaining 2.38 pounds of active ingredient/gallon) was applied as atank mix to a weedy rice field to control 6 tiller barnyard grass at 5pounds propanil plus 0.093 pounds cyhalofop resulted in 100% control ofall grasses, broadleaf weeds and sedges present at time of applicationwhen evaluated 5 and 13 days after application. Note that 5 pounds ofpropanil/acre alone would not be expected to control even one tillerbarnyard grass and the highest label recommended rate for cyhalofopcontrolling large grasses is 15 fluid ounces product/acre (0.278 poundsactive ingredient/acre). The use of 0.093 pounds cyhalofop/acre incombination with 5 pounds of propanil is approximately 3 times lesscyhalofop than the label recommended rate.

Example 5

In a commercial field application by ground sprayer in California acomposition containing propanil (formulated as SUPER WHAM containing 4pounds of active ingredient/gallon) plus cyhalofop (formulated asCLINCHER SF containing 2.38 pounds of active ingredient/gallon) wasapplied as a tank mix to a weedy rice field to control 3-5 leafSprangletop (a grass species) at 6 pounds propanil plus 0.112 poundscyhalofop resulted in 100% control of the Sprangletop present at thetime of application. Note that propanil alone will not controlSprangletop and the recommended rate for cyhalofop to controlSprangletop is 13.5 to 15 fluid ounces product/acre (0.251 to 0.279pounds active ingredient/acre) or approximately 2.2 to 2.5 times lesscyhalofop than the label recommended rate.

Example 6

In a small plot test in Mississippi a composition containing propanil(formulated as SUPER WHAM containing 4 pounds of activeingredient/gallon) plus cyhalofop (formulated as CLINCHER SF containing2.38 pounds of active ingredient/gallon) was applied as a tank mix to aweedy rice plot to control large tillering grasses, broadleaf weeds andsedges at 4 pounds propanil plus 0.149 pounds cyhalofop and at 5 poundspropanil plus 0.093 pounds cyhalofop resulted in the control of allgrasses, broadleaf weeds and sedges present at the time of application.Note that neither the 4 pound nor the 5 pound rates of propanil alonewould be expected to control the weeds at the growth stage they weretreated and that the highest labeled recommended rate of cyhalofop is 15fluid ounces product/acre (0.278 pounds active ingredient/acre) wouldnot control any of the broadleaf weeds or sedges while propanil incombinations with approximately 2 to 3 times less than the recommendedrate of cyhalofop/acre provided weed control.

Example 7

In a small plot test in Arkansas a composition containing propanil(formulated as SUPER WHAM containing 4 pounds of activeingredient/gallon) plus cyhalofop (formulated as CLINCHER SF containing2.38 pounds of active ingredient/gallon) was applied as a tank mix to aweedy rice plot to control 4 to 13 inch barnyard grass and 1 to 6 inchSprangletop (two grass species). The chemical rates in pounds/acre were:

TABLE 4 PROPANIL/CYHALOFOP 5 pounds/0 pounds 5 pounds/0.093 pounds 5pounds/0.130 pounds 4 pounds/0 pounds 4 pounds/0.074 pounds 4pounds/0.112 pounds 3 pounds/0 pounds 3 pounds/0.056 pounds 3pounds/0.093 pounds 3 pounds/0.186 pounds 0 pounds/0.279 pounds

The following observations were made 12 days after application. Allrates of propanil applied showed excellent broadleaf and sedge control.When applied alone, all rates of propanil showed expected lack ofSprangletop control. The treatment of 3 pounds propanil combined with0.186 pounds cyhalofop showed weak grass control that may be attributedto antagonism. The high labeled rate for cyhalofop (0.279 pounds/acre)showed excellent grass control and an expected weakness in controllingbroadleaf weeds and sedges. The combination rates of propanil andcyhalofop other than the 3 pounds propanil combined with 0.186 poundscyhalofop showed broad spectrum weed control of grasses, broadleaf weedsand sedges 12 days after application.

Example 8

In a commercial field application by air in Arkansas a compositioncontaining propanil (formulated as SUPER WHAM containing 4 pounds ofactive ingredient/gallon) plus cyhalofop (formulated as CLINCHER SFcontaining 2.38 pounds of active ingredient/gallon) was applied as atank mix to half a weedy rice field to control up to tillering barnyardgrass at 4 pounds propanil plus 0.037 pounds cyhalofop resulted in 100%control of all grasses, broadleaf weeds and sedges present at time ofapplication when evaluated 7 days after application. The other half ofthe weedy rice field was treated with a composition containing onlypropanil (formulated as SUPER WHAM containing 4 pounds of activeingredient/gallon) at 4 pounds propanil resulting in poor barnyard grasscontrol 7 days after application. Note that 4 pounds of propanil/acrealone would not be expected to control even one tiller barnyard grassand the label recommended rate for cyhalofop controlling large grassesis 15 fluid ounces product/acre (0.279 pounds active ingredient/acre) orapproximately 7.5 times more cyhalofop than was combined with thepropanil.

Example 9

In a commercial field application by air in Arkansas a compositioncontaining propanil (formulated as SUPER WHAM containing 4 pounds ofactive ingredient/gallon) plus cyhalofop (formulated as CLINCHER SFcontaining 2.38 pounds of active ingredient/gallon) was applied as atank mix to a weedy rice field to control up to tillering barnyard grassat 5 pounds propanil plus 0.093 pounds cyhalofop resulted in 100%control of all grasses, broadleaf weeds and sedges present at time ofapplication when evaluated 7 days after application. Note that 5 poundsof propanil/acre alone would not be expected to control even one tillerbarnyard grass and the label recommended rate for cyhalofop controllinglarge grasses is 15 fluid ounces product/acre (0.279 pounds activeingredient/acre), a rate approximately 3 times greater than thatcombined with propanil.

Example 10

In a commercial field application by air in Arkansas a compositioncontaining propanil (formulated as SUPER WHAM containing 4 pounds ofactive ingredient/gallon) plus cyhalofop (formulated as WHIP 360containing 0.57 pounds of active ingredient/gallon) was applied as atank mix to a weedy rice field to control barnyard grass, broadleafweeds and sedges. The weedy rice field was divided into three sections.One section of the weedy rice field was treated only with SUPER WHAM ata rate of 4 pounds of active ingredient (propanil) per acre. A secondsection of the weedy rice field was treated with SUPER WHAM at a rate of3 pounds active ingredient (propanil) plus WHIP at a rate of 0.012pounds active ingredient (fenoxaprop) per acre. The third section of theweedy rice field was treated with SUPER WHAM at a rate of 2.5 poundsactive ingredient (propanil) plus WHIP at a rate of 0.010 pounds activeingredient (fenoxaprop) per acre. In this demonstration the lower rateof propanil plus fenoxaprop, at a rate approximately 7 times lower thanthe highest recommended rate/acre, provided similar or better biologicalactivity than the 4 pound per acre rate of propanil alone at 3 and 7days after application in controlling barnyard grass and broadleaf weedspresent (indigo, morningglory, tea weed, and Ameranthus).

Example 11

In a commercial field application by air in Arkansas a compositioncontaining propanil (formulated as SUPER WHAM containing 4 pounds ofactive ingredient/gallon) plus cyhalofop (formulated as WHIP 360containing 0.57 pounds of active ingredient/gallon) was applied to aweedy rice field to control grass (crab grass) and a broadleaf weed(morningglory). The field was divided into two sections. One section ofthe rice field was treated only with SUPER WHAM at a rate of 4 pounds ofactive ingredient (propanil) per acre. A second section of the ricefield was treated with SUPER WHAM at a rate of 3.5 pounds activeingredient (propanil) plus WHIP at a rate of 0.013 poundsfenoxaprop/acre (a rate of fenoxaprop approximately 5.5 times less thanthe recommended rate/acre). In this demonstration the combination ofpropanil plus fenoxaprop provided similar or better biological activitythan the 4 pound per acre rate of propanil alone at 4 and 8 days afterapplication in controlling both the crab grass and morningglory.

Example 12

In a small plot test in Colombia a composition containing propanil(formulated as an emulsifiable concentrate containing 480 grams ofactive ingredient/liter) plus fenoxaprop (formulated as Furorecontaining 45 grams active ingredient/liter) was applied to rice tocontrol germinating to tillering grasses, germinating to 2-3 leafbroadleaf weeds and germinating to 2-5 leaf sedges. In this testpropanil was applied at rates of 3.36, 3.00, and 2.75 kg activeingredient alone and in combinations with fenoxaprop at rates of 0.85,0.30, 0.20, 0.10 and 0.05 kg active ingredient per hectare. Thefenoxaprop rates listed above were also applied alone, without propanil.In this test the combinations of propanil at 3.36, 3.00 and 2.75 kg plusfenoxaprop at 0.10 kg per hectare provided superior control of grasses(Echinochloa colonum, Eleusine indica, and Digitaria sanguinalis),broadleaf weeds (Cassia tora and Ammania coccinea) and sedge (Cyperusrotundus) than any propanil or fenoxaprop rate alone.

Example 13

Based on the results of Example 10, in a second small plot test inColombia a composition containing propanil (formulated as anemulsifiable concentrate containing 480 grams of active ingredient/literand as a wetable granule containing 800 grams of active ingredient/kg)plus fenoxaprop (formulated as Furore containing 45 grams activeingredient/liter) was applied to rice to control grasses, leaf broadleafweeds and leaf sedges. In this test, the treatments were made at twodifferent timings. The grasses (Echinochloa colonum, Ischaemum rugosum,Rottboellia cochinchinensis, and Digitaria sanguinalis) were in the 1 to3 leaf stage for the first timing and in the 4 leaf to 1 tiller stagefor the second timing. The broadleaf weeds (Ipomeoa sp., Jussiaealinifolia and Ammania coccinea) were between the 2 to 4 leaf stage forthe first timing and more than 4 leaf stage for the second timing. Thesedges (Fimbristilis annua and Cyprus feraz) were in the 2 to 5 leafstage for the first timing and more than 5 leaf stage for the secondtiming). In this test the propanil formulations were evaluated at 3.6,2.7, 1.8, and 0.9 kg active ingredient/hectare alone and in combinationwith 0.01, 0.0075, 0.005 and 0.0025 kg fenoxaprop/hectare respectively.The propanil+fenoxaprop combination rates of 3.6+0.01 and 2.7+0.0075kg/hectare gave superior weed control, particularly evident at thesecond timing on larger more difficult to control weeds, than thepropanil treatments alone.

Example 14

In a small plot test in Colombia a composition containing propanil(formulated as an emulsifiable concentrate containing 480 grams ofactive ingredient/liter) plus cyhalofop (formulated as CLINCHERcontaining 180 grams active ingredient/liter) was applied to rice tocontrol grasses, leaf broadleaf weeds and leaf sedges. In this test, thetreatments were made at two different timings. The grasses (Echinochloacolonum, Ischaemum rugosum, Rottboellia cochinchinensis, and Digitariasanguinalis) were in the 1 to 3 leaf stage for the first timing and inthe 4 leaf to 1 tiller stage for the second timing. The broadleaf weeds(Ipomeoa sp., Jussiaea linifolia and Ammania coccinea) were between the2 to 4 leaf stage for the first timing and more than 4 leaf stages forthe second timing. The sedges (Fimbristilis annua and Cyprus feraz) werein the 2 to 5 leaf stage for the first timing and more than 5 leaf stagefor the second timing). A series of propanil rates (0.840, 1.12, 1.40,1.68, 2.24, 2.52, 2.80, 3.36, 4.20, 4.48, and 5.60 kg activeingredient/hectare) were combined with cyhalofop at a constant ratio of0.0186 kg cyhalofop/hectare for every 1 kg propanil/hectare (0.0156,0.0208, 0.0261, 0.0313, 0.0417, 0.0469, 0.0521, 0.0625, 0.0782, 0.0834,and 0.1042 kg cyhalofop/hectare respectively). The propanil+cyhalofopcombination rates at 2.52+0.0469 kg/hectare and above gave weed control,particularly evident at the second timing on larger more difficult tocontrol weeds, than the lowest commonly recommended propanil rate (3.36kg/hectare) alone (see example 11 for weed control with propanil alonethat was conducted at the same time and location as this teat).

Although the present invention has been described and illustrated withrespect to preferred embodiments and a preferred user thereof, it is notto be so limited since modifications and changes can be made thereinwhich are within the full scope of the invention.

1. A method to use at least 20 percent less propanil based herbicide tocontrol weeds, while cultivating rice in a field, comprising the stepsof: applying to said field an amount of a propanil based herbicide witha herbicidally ineffective amount of cyhalofop, to form a herbicidallyeffective composition, wherein the weight ratio of the herbicidaleffective compound ranges from about 1 pound of propanil to about 0.009to 0.04 lbs. of cyhalofop wherein the amount of propanil applied isselected from the group consisting of: the weeds are grass at 2 to 3leaf stage and the amount of propanil is 2 pounds per acre; wherein theweeds are grass at 3 to 4 leaf stage and the amount of propanil is 3pounds per acre; wherein the weeds are grass at 4 to 5 leaf stage andthe amount of propanil is 4 pounds per acre and wherein the weeds aregrass at 5 leaf stage and wherein the weeds are grass at 6 leaf stageand the amount of propanil is 6 pounds per acre.
 2. The method of claim1 wherein said composition comprises as an active ingredient aneffective amount of a compound selected from the group consisting ofinsecticide, fungicide, bactericide, acaracide, nematicide, plant growthregulator, fertilizer, and plant nutrients.
 3. The method of claim 1wherein the propanil based herbicide and cyhalofop are individuallyapplied to said field within 24 hours of each other.
 4. The method ofclaim 1 wherein said propanil based herbicide and said herbicidallyineffective amount of cyhalofop is tank mixed.
 5. The method of claim 1further comprising adding a herbicide selected form the group consistingof thiocarbamates, chloroacetamides and auxins, wherein said weeds arelarger than at a 6 leaf stage.